Thermo-oxidatively Stable, Side Chain Polyether Functionalized Polynorbornenes for Microelectronic and Optoelectronic Devices and Assemblies Thereof

ABSTRACT

The present invention relates to polynorbornene (PNB) composition embodiments that are useful for forming microelectronic and/or optoelectronic devices and assemblies thereof, and more specifically to compositions encompassing PNBs having norbornene-type repeating units that are polyether functionalized where such the PNBs of such compositions and the microelectronic and/or optoelectronic devices made therefrom are resistant to thermo-oxidative chain degradation of said polyether functionalization.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to Provisional PatentApplication Ser. No. 61/586,950 filed Jan. 16, 2012 and ProvisionalPatent Application Ser. No. 61/601,752 filed Feb. 22, 2012, the entirecontents of which are incorporated herein by reference.

TECHNICAL FIELD

Embodiments in accordance with the present invention relate generally topolynorbornene (PNB) compositions that are useful for formingmicroelectronic and/or optoelectronic devices and assemblies thereof,and more specifically to compositions encompassing PNBs havingnorbornene-type repeating units that are polyether functionalized wheresuch PNBs are resistant to thermo-oxidative chain degradation of saidpolyether functionalization.

BACKGROUND

Organic polymer materials are increasingly being used in themicroelectronics and optoelectronics industries for a variety ofapplications. For example, the uses for such organic polymer materialsinclude interlevel dielectrics, redistribution layers, stress bufferlayers, leveling or planarization layers, alpha-particle barriers formicroelectronic and optoelectronic devices. Such devices includingmicroelectromechanical systems and optoelectromechanical systems as wellas the direct adhesive bonding of devices and device components to formsuch systems. Where such organic polymer materials are photosensitive,and thus self-imageable, they offer the additional advantage of reducingthe number of processing steps required for the use of such layers andstructures made therefrom.

While polyimide (PI), polybenzoxazole (PBO) and benzocyclobutane (BCB)compositions have been materials of choice for many of theaforementioned applications due to their generally good thermalstability and mechanical strength, each of the above materials areeither formed during curing from precursors that react to modify thepolymer's backbone (PI and PBO) or to form such backbone (BCB) and thusgenerally require special handling conditions during curing to removeby-products that are formed during such curing and/or to exclude oxygenor water vapor that can prevent such curing. Additionally, the curing ofsuch materials often requires process temperatures in excess of 250° C.(and as high as 400° C. for some materials). Therefore such materialscan be problematic for some applications, e.g., redistribution andinterlayer dielectric layers as well as direct adhesive bonding of atransparent cover over image sensing arrays.

Therefore it is believed that it would be advantageous to provide amaterial, useful for forming the aforementioned structures, thatexhibits thermal stability and mechanical strength equivalent to theknown PI, PBO, and BCB compositions, where such a material has a fullyformed polymer backbone that allows for curing at temperatures of 200°C. or lower. Further, such an advantageous material should be tailorablein its characteristics to provide appropriate levels or values ofstress, modulus, dielectric constant, elongation to break andpermeability to water vapor for the application for which it isintended. Still further, it would be advantageous for such a material tobe self-imageable.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments in accordance with the present invention are describedhereinbelow with reference to the following accompanying drawings.

FIG. 1 is a chart showing the weight loss of polymers P9 and P14 over600 minutes while heated to 200° C.;

FIG. 2 is a box plot graph showing normalized elongation to break ofFormulation embodiments F44, F45, F46, F53 and F55 during hightemperature stability testing (HTS) at 150° C. in air for 100 hours;

FIG. 3 is a box plot graph showing normalized elongation to break ofFormulation embodiments F57-F60 measured during high temperaturestability testing (HTS) at 150° C. in air for 200 hours;

FIG. 4 is a box plot graph showing normalized elongation to break ofFormulation embodiments F61-F64 measured during high temperaturestability testing (HTS) at 150° C. in air for 200 hours; and

FIG. 5 is a box plot graph showing normalized elongation to break ofFormulation embodiments F65-F68 measured during high temperaturestability testing (HTS) at 150° C. in air for 200 hours.

DETAILED DESCRIPTION

Embodiments in accordance with the present invention are directed tonorbornene-type polymers, self-imageable compositions that encompasssuch polymers and the films, layers, structures, devices or assembliesthat can be formed using such polymers and compositions. Some of suchembodiments encompass self-imageable compositions which can providepositive-tone images, after image-wise exposure of a film formedthereof, followed by development of such images, using an aqueous basedeveloper solution. While other of such embodiments encompassself-imageable compositions which can provide negative-tone images,after image-wise exposure of a film formed thereof, followed bydevelopment of such images, using an appropriate solvent baseddeveloper.

Further, the aforementioned embodiments can routinely provide thickfilms of 5 microns (μm) or greater and images demonstrating aspectratios in excess of 1:2 for isolated line/trench resolution in suchfilms. The films, layers, and structures formed from the polymerembodiments of the present invention being useful for, among otherthings, interlevel dielectrics, redistribution layers, stress bufferlayers, leveling or planarization layers, alpha-particle barriers forboth microelectronic and optoelectronic devices and the assembliesformed thereof, as well as adhesive bonding to form chip-stacks and tofixably attach transparent covers over image arrays.

Unless otherwise indicated, all numbers, values and/or expressionsreferring to quantities of ingredients, reaction conditions, polymercompositions, and formulations used herein are to be understood asmodified in all instances by the term “about” as such numbers areinherently approximations that are reflective of, among other things,the various uncertainties of measurement encountered in obtaining suchvalues. Further, where a numerical range is disclosed herein, such rangeis continuous, and includes unless otherwise indicated, every value fromthe minimum value to and including the maximum value of such range.Still further, where such a range refers to integers, unless otherwiseindicated, every integer from the minimum value to and including themaximum value is included. In addition, where multiple ranges areprovided to describe a feature or characteristic, such ranges can becombined to further describe such a feature or characteristic.

As used herein, the articles “a,” “an,” and “the” include pluralreferents unless otherwise expressly and unequivocally limited to onereferent.

It will be understood that, as used herein, the phrase “microelectronicdevice” is inclusive of a “micro-optoelectronic device” and an“optoelectronic device”. Thus, reference to microelectronic devices or amicroelectronic device assemblies are inclusive of optoelectronicdevices and micro-optoelectronic devices as well as assemblies thereof.

It will be understood that the terms “dielectric” and “insulating” areused interchangeably herein. Thus, reference to an insulating layer isinclusive of a dielectric layer.

As used herein, the term “polymer” will be understood to mean a moleculethat encompasses a backbone of one or more distinct types of repeatingunits (the smallest constitutional unit of the polymer) and is inclusiveof, in addition to the polymer itself, residues from initiators,catalysts, and other elements attendant to the forming of such apolymer, where such residues are understood as not being covalentlyincorporated thereto. Further, such residues and other elements, whilenormally removed during post polymerization purification processes, aretypically mixed or co-mingled with the polymer such that some smallamount generally remains with the polymer when it is transferred betweenvessels or between solvents or dispersion media.

As used herein, the term “polymer composition” is meant to include atleast one synthesized polymer, as well as materials added after theforming of the polymer(s) to provide or modify specific properties ofsuch composition. Exemplary materials that can be added include, but arenot limited to, solvents, photoactive compounds (PAC), dissolution rateinhibitors, dissolution rate enhancers, crosslinking moieties, reactivediluents, antioxidants, adhesion promoters, and plasticizers.

As used herein, the term “modulus” is understood to mean the ratio ofstress to strain and unless otherwise indicated, refers to the Young'sModulus or Tensile Modulus measured in the linear elastic region of thestress-strain curve. Modulus values are generally measured in accordancewith ASTM method DI708-95. Films having a low modulus are understood toalso have low internal stress.

The term “photodefinable” refers to the characteristic of a material orcomposition of materials, such as a polymer or polymer composition inaccordance with embodiments of the present invention, to be formed into,in and of itself, a patterned layer or a structure. In alternatelanguage, a “photodefinable layer” does not require the use of anothermaterial layer formed thereover, for example a photoresist layer, toform the aforementioned patterned layer or structure. It will be furtherunderstood that a polymer composition having such a characteristic isgenerally employed in a pattern forming scheme to form a patternedfilm/layer or structure. It will be noted that such a schemeincorporates an “imagewise exposure” of the photodefinable material orlayer formed therefrom. Such imagewise exposure being taken to mean anexposure to actinic radiation of selected portions of the layer, wherenon-selected portions are protected from such exposure to actinicradiation.

As used herein, the term “self-imageable compositions” will beunderstood to mean a material that is photodefinable and can thusprovide patterned layers and/or structures after direct image-wiseexposure of a film formed thereof followed by development of such imagesin the film using an appropriate developer.

As used herein, “hydrocarbyl” refers to a radical of a group thatcontains only carbon and hydrogen atoms, non-limiting examples beingalkyl, cycloalkyl, aryl, aralkyl, alkaryl, and alkenyl. The term“halohydrocarbyl” refers to a hydrocarbyl group where at least onehydrogen atom has been replaced by a halogen atom. The termperhalocarbyl refers to a hydrocarbyl group where all hydrogens havebeen replaced by halogens. The term “heterohydrocarbyl” refers to any ofthe previously described hydrocarbyls, halohydrocarbyls, andperhalohydrocarbyls where at least one carbon atom of the carbon chainis replaced with a N, O, S, Si or P atom. Non-limiting examples includeheterocyclic aromatic groups such as pyrrolyl, furanyl, and the like, aswell as non-aromatic groups such as ethers, thioethers and silyl ethers.The term “alkylol” refers specifically to heteroalkyl groups thatinclude one or more hydroxyl (—OH) groups. Non-limiting examples includeNBCH₂OH, NBEtOH, NBBuOH, NBCH₂OCH₂CH₂OH, and NBCH(CH₂OH)₂, where “NB”refers to Structural Formula I.

As used herein, “alkyl” refers to a linear or branched acyclic orcyclic, saturated hydrocarbon group having a carbon chain length of, forexample, from C₁ to C₂₅. Non-limiting examples of suitable alkyl groupsinclude, but are not limited to, —CH₃, —C₂H₅, —(CH₂)₃CH₃, —(CH₂)₄—CH₃,—(CH₂)₅CH₃, —(CH₂)₉CH₃, —(CH₂)₂₃CH₃, cyclopentyl and cyclohexyl.

As used herein the term “aryl” refers to aromatic groups that include,without limitation, groups such as phenyl, biphenyl, xylyl,naphthalenyl, anthracenyl and the like.

The terms “alkaryl” or “aralkyl” are used herein interchangeably andrefer to a linear or branched acyclic alkyl group substituted with atleast one aryl group, for example, phenyl, and having an alkyl carbonchain length of C₁ to C₂₅. Non-limiting examples would be benzyl,phenethyl, and phenbutyl. It will further be understood that the aboveacyclic alkyl group can be a haloaralkyl or perhaloaralkyl group.Non-limiting examples would be pentafluorophenmethyl,pentafluorophenethyl, and pentafluorophenbutyl.

As used herein the term “alkenyl” refers to a linear or branched acyclicor cyclic hydrocarbon group having one or more double bonds and havingan alkenyl carbon chain length of C₂ to C₂₅. Non-limiting examplesinclude, among others, ethenyl or vinyl groups, propenyl, butenyl,cyclohexenyl, and the like.

It will additionally be understood that any of the hydrocarbyl,halohydrocarbyl and perhalohydrocarbyl moieties, or their “hetero”analogs, described above can be further substituted, if desired, or canbe a divalent radical thereof. Non-limiting examples of suitablesubstituent groups include, among others, hydroxyl groups, carboxylicacid and carboxylic acid ester groups, amides and imides.

As used herein, the terms “polycycloolefin”, “poly(cyclic) olefin”, and“norbornene-type” are interchangeably used to refer to additionpolymerizable monomers, the resulting repeating units in the resultingpolymers or the compositions that encompass such polymers, where suchmonomers, repeating units of such resulting polymers encompass at leastone norbornene-type moiety. The simplest norbornene-type polymerizablemonomer encompassed by embodiments in accordance with the presentinvention is norbornene itself, bicyclo[2.2.1]hept-2-ene, as shownbelow:

However, the term norbornene-type monomer, norbornene-type repeatingunit or norbornene-type polymer (PNB) as used herein is not limited tosuch moieties that encompass only norbornene itself, but rather to anysubstituted norbornene(s), or substituted and unsubstituted highercyclic derivatives thereof.

Published US Patent Application No. US 2011-0070543 A1 (the '543publication) discloses a negative tone, aqueous-base developable PNBcomposition that encompasses anorbornenyl-2-trifluoromethyl-3,3,3-trifluoropropan-2-ol (HFANB)/Ethylnorbornenylpropanoate (EPEsNB) polymer having a molar ratio of 75/25,with a photo acid generator compound (PAG), a photo sensitizer, adhesionpromoters, and crosslinker additives, e.g., Example 12-8. Further, such'543 publication discloses, in Examples 12-1, 12-2 and 12-3, positivetone compositions that encompass the aforementioned polymer andappropriate additives. This reference to the above Examples of the '543publication is provided to establish that the current state of the art,to which this disclosure is directed only provided a negative tonecomposition having acceptable self-imaging capability since the positivetone compositions that were provided did not exhibiting an acceptableself-imagining capability.

Still further, while the '543 publication discloses polymers and polymercompositions that encompass trioxanonanenorbornene (NBTON), it was foundthat such NBTON-containing compositions despite having advantageouscharacteristics and/or properties such compositions did not exhibitacceptable positive tone imageability.

In general, polymer composition embodiments of the present inventionsuitable as positive tone compositions exhibit one or more of thefollowing characteristics in addition to being self-imageable andcapable of resolving isolated line/trench features having an aspectratio of greater than 1:2 in polymer films having a thickness of atleast 5 μm:

-   -   i. Positive tone photolithography patterning with 0.26N TMAH        developer, or other commonly employed aqueous base developer,        solubility;    -   ii. A dielectric constant of less than 4;    -   iii. Good oxidative stability, as measured by the stability of        the polymer's elongation to break (ETB) during HTS stability        testing at 150° C. for 100 hours;    -   iv. Direct contact adhesion to glass and/or silicon wafers        during an appropriate thermocompression bonding process; and    -   v. A low modulus, or internal stress, of a cured polymer film.

Although the '543 publication disclosures a family of aqueous basedevelopable PNB compositions, as mentioned above, such family does notinclude positive tone, aqueous base developable polymer compositions.

As mentioned above, some polymer composition embodiments in accordancewith the present invention encompass negative-tone photodefinablepolymers. Such embodiments being useful for direct adhesive bonding, asdescribed herein, or as dielectric or redistributions layers, as alsodescribed herein. Further, such embodiments exhibit one or more of thefollowing characteristics, in addition to being self-imageable andcapable of resolving isolated line/trench features having an aspectratio of greater than 1:2 in polymer films having a thickness of atleast 5 μm:

-   -   a. Negative tone photolithography patterning with an appropriate        solvent developer;    -   b. A dielectric constant of less than 6;    -   c. An appropriate level of permeability to water vapor;    -   d. Direct contact adhesion to glass and/or silicon during an        appropriate thermo-compression bonding process; and    -   e. A low modulus, or internal stress, of a cured polymer film.

Structural Formula I and Ia shown below, are representative ofnorbornene-type monomers and corresponding norbornene-type repeatingunits, respectively, that are in accordance with embodiments of thepresent invention:

where for each of Formulae I and Ia, X is selected from —CH₂—,—CH₂—CH₂—, O and S; m is an integer from 0 to 5 and each occurrence ofR¹, R², R³ and R⁴ independently represents hydrogen, a hydrocarbyl oranother substituent.

Norbornene-type polymers present in polymer composition embodiments inaccordance with the present invention are derived from a 2,3 enchainmentpolymerization process (also known as vinyl addition polymerization) andhave at least two distinct types of repeat units, and in someembodiments as many as three, four or five distinct types of repeatunits, in accordance with Structural Formula Ia, that are derived frommonomers in accordance with Formula I, as described above.

Exemplary polymer embodiments in accordance with the present invention,encompass a first of the at least two distinct types of repeating unitshaving one of R¹-R⁴ being a radical represented by Formula A where s isselected from 0 to 3, t is selected from 2 to 4, u is selected from 1 to3, and R⁷ is selected from methyl, ethyl, n-propyl or i-propyl.

Such distinct type of repeat unit being useful for providing a desireddegree of stress, modulus, plasticization, adhesion, and water vaporpermeability. Additionally, the short polyether side chains impartsimproved aqueous base solubility for a positive tone formulationcompared to incorporating a C₈-C₁₂ alkyl pendent group, e.g. an n-decylpendent group, while still allowing for solubility in appropriatesolvent developers for negative tone formulations.

In some embodiments a repeating unit encompassing such pendent group, orradical in accordance with Formula A, is derived from the followingnorbornene-type monomers: NBCH₂(OCH₂CH₂)₃OCH₃ (NBTODD),NBCH₂(OCH₂CH₂)₂OCH₃ (NBTON), NBCH₂CH₂(OCH₂CH₂CH₂)OCH₃ (NB-3-MBM) orNBCH₂—(OCH₂CH₂CH₂)OCH₃ (NB-3-MPM), where “NB” refers to StructuralFormula I.

While all polymer embodiments in accordance with the present inventionencompass the above described first distinct type of repeating unit, asit will be seen below, other repeating units encompassed by such polymerembodiments are selected to provide properties to such polymerembodiments that are appropriate and desirable for the use for whichsuch embodiments are directed, thus such polymer embodiments aretailorable to a variety of specific applications.

For example, polymer embodiments generally require at least onerepeating unit directed to providing imageability. Thus distinct typesof repeating units, represented by Structural Formula Ia, can includeone of R¹-R⁴ being a carboxylic acid containing heterohydrocarbylpendent group. That is to say, that such one of R¹-R⁴ is represented bythe formula R⁵COOH, where R⁵ is a C₁ to C₈ alkyl divalent radical, suchas, for example, —CH₂CH₂—, thus being the carboxylic acid containingpendent group —CH₂CH₂COOH. Carboxylic acid pendent groups are generallyuseful for participating in a reaction with appropriately selectedadditives, or other repeating units, that can lead either to theformation of an image for negative-tone embodiments or to fix apositive-tone image via post develop thermal crosslinking.

Such exemplary polymer embodiments can alternately, or additionally,encompass a distinct type of repeat unit having one of R¹-R⁴ being apendent hydrocarbyl group, not containing carboxylic acid functionality,having a dissociable hydrogen atom with a pK_(a) less than 11. That isto say, that such one of R¹-R⁴ is, for example, a pendent group having astructure in accordance with one of formula B:

where R⁶ is selected from —(CH₂)_(p)—, —(CH₂)_(q)—OCH₂— or—(CH₂)_(q)—(OCH₂CH₂)_(r)—OCH₂—, where p is an integer from 0 to 6, q isan integer from 0 to 4 and r is an integer from 0 to 3.

More specifically, some such embodiments that encompass a pendent groupin accordance with formula B, have R⁶ being the divalent radical—CH₂CH₂OCH₂—, such repeating unit can be namednorbornenylethoxy-2-trifluoromethyl-3,3,3-trifluoropropan-2-ol (ornorbornenyl ethoxymethylhexafluoropropanol, NBEMHFP). For some othersuch polymer embodiments R⁶ of such second repeating unit is —CH₂OCH₂—,such repeating unit can be named norbornenylmethoxy2-trifluoromethyl-3,3,3-trifluoropropan-2-ol (or norbornenylmethoxymethylhexafluoropropanol, NBMMHFP). For still other polymerembodiments, R⁶ of such repeating unit is —CH₂—, and such repeat unitcan be named norbornenyl-2-trifluoromethyl-3,3,3-trifluoropropan-2-ol(HFANB). Such alternate or additional distinct types of repeating unitsbeing useful for providing linear dissolution in aqueous basedevelopers, as well as, in some cases, cross-linking.

Exemplary polymer embodiments in accordance with the present inventionthat exhibit cross-linking either to form an image or to fix an imagecan encompass one or more other distinct types of repeating units usefulfor cross-linking with one or both of previously described distinctrepeating units useful for cross-linking. For example, repeat unitshaving pendent groups in accordance with any of Formulae C, D, E and F:

where R^(5a), if present, is a —(CH₂)_(n)—O— radical where n is from 1to 6 and R⁶, if present, is a C₁ to C₁₂ alkyl moiety. As will bediscussed below, repeat units containing a pendent group in accordancewith Formulae C, D, E or F are generally useful for participating inreactions that are useful in cross-linking of such polymer compositions;repeat units containing a pendent group in accordance with Formula F arealso generally useful for improving the adhesion of a film formedtherefrom. It should be noted that non-polymeric cross-linking additivescan be employed, in polymer composition embodiments of the presentinvention, as either an alternate to the aforementioned repeating unitsor in addition to such repeating units.

Some polymer embodiments in accordance with the present invention caninclude repeat units having a hindered phenol type pendent group, forexample a pendent group in accordance with Formula G:

where R^(6a), if present, is a C₁ to C₄ alkyl moiety.

While the polymer composition embodiments of the present invention havebeen described as encompassing a polymer having at least two distincttypes of repeat units, such polymer compositions are not so limited.Thus some polymer composition embodiments can encompass a polymer havingas many as three, four or five distinct repeating units, with theproviso that all such polymers encompassed by the polymer compositionsof the present invention have a repeat unit that encompasses a pendentgroup represented by Formula A.

The polymer composition embodiments in accordance with the presentinvention also provide for stabilizing of short polyether pendentgroups. It will be understood that where the thermo-oxidative stabilityof such pendent groups can be maintained in a film or structure madefrom such a polymer composition, the desirable characteristics of arepeat unit containing such a pendent group can be maintained.

Technical literature describes that polyethylene oxide based polymerswill degrade rapidly in air at elevated temperature. While not wishingto be bound by theory, it is believed that hindered phenol typeantioxidants interrupt the autocatalytic oxidation cycle by stabilizingthe peroxide radical (III) (see, Scheme A) that is formed afteroxidative degradation begins and was believed to be sufficient toprevent further oxidative degradation as indicated in Scheme A:

Therefore, to our surprise, incorporating a repeat unit derived from amonomer having a hindered phenol pendent group (shown by Formula G) suchas AO2NB monomer(4,4′-(bicyclo[2.2.1]hept-5-en-2-ylmethylene)bis(2,6-di-tert-butylphenol)into a polymer embodiment of the present invention or including hinderedphenol anti-oxidant additives, such as those mentioned in previouslycited US Patent Application No. US 2011-0070543 A1, i.e., Irganox® 1076,Irganox 1010, or sulfur containing phenols, were not effective atpreventing the rapid oxidative degradation of repeat units having apendent group in accordance with Formula A, such as repeat units derivedfrom a NBTON monomer. Rather, rapid thermo-oxidative degradation of thependent group to form products V, VI, and VII, shown below in Scheme B,occurs. Further, while not wishing to be bound by theory, we believethat the continued fragmentation of a polyethylene oxide chain occurseven when a hydrogen peroxy group (III) has formed in the alpha positionto an ether oxygen in a polyethylene oxide chain. In this instance, the“stabilized group” III which would be expected to be stable and not tocontinue a degradation process, thus it was found that III continues toact as a reactive chain breaking moiety, as indicated in the schemebelow:

Therefore, alternate approaches for providing thermo-oxidative stabilityto the PNB polymer and composition embodiments of the present inventionwere developed as the result of careful study and experimental efforts.Thus it was found that improved oxidative stability can be achieved byemploying a different AO additive strategy for polymer compositionembodiments of the present invention. Specifically, such different AOadditive strategy encompasses the use of diaryl amine compounds, e.g.Naugard 445, to inhibit the oxidative degradation. It was also found, asshown in Scheme C, that improved oxidative stability can be achieved bychanging the number of methylene (—CH₂—) spacers between thepoly(alkylene oxide) ether oxygen linkages, for example oxygen a and b,to prevent the unexpected, facile degradation of structure III as shownin Scheme B and it's analog VIII shown in Scheme C, below. Thus it isseen that the addition of an single extra methylene spacer betweenoxygen a and b of structure III, to form the analog structure VIII,would prevent the favorable alignment of the oxygen atoms into the6-membered orientation shown in Scheme B and provide the unfavorablealignment shown in Scheme C. Thus preventing, or at least minimizing,the undesirable decomposition to products IX, X and XI shown in SchemeC, below:

Referring now to FIG. 1, a chart showing the percent weight loss of afirst polymer (P9) having a repeat unit derived from a NBTON monomer(NBEtCO₂H/HFANB/NBTON), and a second polymer (P14) having a repeat unitderived from a NB-3-MPM monomer (NBEtCO₂H/HFANB/NB-3-MPM), as eachpolymer was heated at 200° C. for 600 minutes is provided. As seen,polymer P14, having the repeat unit derived from a NB-3-MPM monomer, andthus having the additional methylene spacer as discussed above, showsconsiderably less weight loss than polymer P9. This result beingsupportive of the above discussion as to how oxidative degradation islikely occurring.

However, while the use of repeat units derived from monomers such asNB-3-MPM or NB-3-MBM (see, Examples M1 and M2, respectively), can beadvantageous, the effect of non-polymeric additives was also explored.More specifically, since diaryl amine compounds, such as theaforementioned Naugard 445, (NG445) are known to be employed for mainchain stabilization of polyethers, their effect on the stability ofpolymer formulation embodiments of the present invention was studied. Toconduct this study, polymer formulation embodiments F18-F31 werethermogravimetrically tested by heating samples of each formulationisothermally, at 180° C. for 2 hours, in a nitrogen atmosphere. Theresults of this study are summarized in Table 7, below. While again notwishing to be bound by theory, it is believed that any observed weightloss is related, in significant part, to the degradation of the shortside chain polyether pendent groups in the presence of a strong organicacid, which can be seen to be mitigated by the presence of the diarylamine synergist NG445.

Turning now to FIG. 2, a box plot graph is seen that compares thenormalized elongation to break of Formulations F44, F45, F46, F53 andF55 obtained during an isothermal, high temperature stability testing(HTS) at 150° C., in air, for 100 hours. In this test, both the thermaland oxidative degradation of the formulations is evaluated by theheating in air as opposed to a nitrogen atmosphere. Further, asthermo-oxidative degradation is known to result in a polymer showing areduction in its elongation to break, it is believed that any change inelongation to break of the polymers of formulations F44, F45, F46, F53and F55 is indicative of thermo-oxidative degradation. It will beunderstood that each result depicted in the box plot graph shows a boxthat represents 50% of the measured data. The upper boundary of the boxrepresents the third quartile boundary (75% of the data is less thanthis value), while the lower box boundary represents the first quartileboundary (25% of the data is less than this value). The line between theupper and lower box boundaries represents the second quartile boundary(50% of the data is less than this value) and the upper and lowervertical lines, whiskers, extend to the maximum data point within 1.5box heights from the top and bottom of the box, respectively. It shouldbe noted that each of Formulations F44, F45 and F46 encompass polymer P9(HFANB/NBEtCOOH/NBTON), formulation F53 encompasses polymer P12(HFANB/NBEtCOOH/NBTON/AO2NB) and formulation F55 encompasses polymer P14(HFANB/NBEtCOOH/NB-3-MPM). Therefore only formulation F55 has a repeatunit derived from NB-3-MPM which has an additional methylene spacerbetween the polyether oxygens of its pendent group. As for formulationF53, polymer P12 includes a repeat unit derived from an AO2NB monomer.That is to say, a monomer having a hindered phenol type pendent group.Thus F44, F53 and F55 do not have any antioxidant or synergistadditives, while F45 has only the antioxidant additive and F46 has boththe antioxidant and synergist additives (see, Table 11). Thus it can beseen from the box plot of FIG. 2 that F44 and F53 show the highestreduction in elongation to break, the worst results, while F46 and F55show the best results, that is to say show the best thermo-oxidativestability of the five formulations presented in FIG. 2.

Turning now to FIGS. 3, 4 and 5, a more exhaustive study ofthermo-oxidative stability is provided. Collectively these three figuresprovide elongation to break data for twelve formulations (F57-F68) thatwhere heated for 200 hours. Referring to Table 12, the full complementof additives included with polymer P9 (HFANB/NBEtCOOH/NBTON) for eachformulation is provided. As it can be seen, formulations F58, F61 andF65 show the most stable elongation to break values.

Exemplary aromatic diamine compounds that act as antioxidant synergistsor synergists or stabilizers include, but are not limited to,4,4′-dimethyldiphenylamine (TCI America, Portland, Oreg.),4,4′-dimethoxydiphenylamine (Thermoflex, E.I. du Pont Nemours & Co.,Wilmington, Del.), N,N′-di-2-naphthyl-p-phenylenediamine (Agerite White,TCI America, Portland, Oreg.), di-tert-butyl-diphenylamine (StearerStar, TCI America, Portland, Oreg.),4,4′-bis(α,α-dimethylbenzyl)diphenylamine (Naugard 445, Chemtura,Middlebury, Conn.), Irganox 5057 (BASF America, Florham Park N.J.),Irganox-57L (BASF America, Florham Park N.J.) and Wingstay 29 (Eliochem,Villejust, France). It has been found that in general, such materialsare effective at loadings from 1 parts per hundred resin (pphr) polymerto 20 pphr polymer. However it should be understood that loadings higheror lower may also prove effective as their efficacy is dependent, atleast in part, on the nature and loading of the phenolic materialemployed.

Exemplary phenolic compounds that can act as primary anti-oxidantsinclude, among others,2,2′-(2-hydroxy-5-methyl-1,3-phenylene)bis(methylene)bis(4-methylphenol)(Antioxidant-80) (TCI America, Portland, Oreg.),6,6-methylenebis(2-(2-hydroxy-5-methylbenzyl)-4-methylphenol) (4-PC,DKSH, North America),6,6′-(2-hydroxy-5-methyl-1,3-phenylene)bis(methylene)bis(2-(2-hydroxy-5-methylbenzyl)-4-methylphenol)(DKSH, North America),6,6′-methylenebis(2-(2-hydroxy-3,5-dimethylbenzyl)-4-methylphenol)(DKSH, North America),6,6′-(2-hydroxy-5-methyl-1,3-phenylene)bis(methylene)bis(2,4-dimethylphenol)(DKSH, North America), Lowinox® 22M46 (Chemtura, Middlebury, Conn.),Lowinox 221B46 (Chemtura, Middlebury, Conn.), Lowinox 44B25 (Chemtura,Middlebury, Conn.), Lowinox CA-22 (Chemtura, Middlebury, Conn.), LowinoxAH-25 (Chemtura, Middlebury, Conn.) and Lowinox-CPL (Chemtura,Middlebury, Conn.). It has been found that in general, such materialsare effective at loadings from 1 pphr polymer to 20 pphr polymer.However it should be understood that loadings higher or lower may alsoprove effective as their efficacy is dependent, at least in part, on thenature and loading of the diaryl amine material employed.

Polymer formulation embodiments in accordance with the present inventioncan exhibit positive tone imageability or negative tone imageability.Where positive tone imageability is desired, it has been found that aphotosensitive material can be incorporated into the composition. Suchmaterials selected to provide positive tone imageability generallyencompass a 1,2-naphthoquinonediazide-5-sulfonylic structure and/or a1,2-naphthoquinonediazide-4-sulfonylic structure represented instructural Formulae (2a) and (2b), respectively:

and benzoquinone diazide materials as represented in structural Formula(2c):

Generally the structures of Formulae (2a), (2b) and/or (2c) areincorporated into the photosensitive composition as an esterificationproduct of the respective sulfonyl chloride (or other reactive moiety)and a phenolic compound, such as one of structures 3a through 3f shownbelow, each generally referred to as a photoactive compound or PAC.Thus, any one, or any mixture of two or more of such PACs are combinedwith the polymer in forming a positive tone polymer compositionembodiment of the present invention. In each of Formulae (3), Qrepresents any of the structures of Formulae 2a, 2b or 2c.Advantageously, when a portion of a film or a layer of thephotosensitive composition is exposed to appropriate electromagneticradiation, these esterification products generate a carboxylic acidwhich enhances the solubility of such exposed portion in an aqueousalkali solution as compared to any unexposed portions of such film.Generally such photosensitive materials are incorporated into thecomposition in an amount from 5 to 50 pphr polymer. Where the specificratio of the photosensitive material to polymer is a function of thedissolution rate of exposed portions as compared to unexposed portionsand the amount of radiation required to achieve a desired dissolutionrate differential. Advantageous photosensitive materials useful inembodiments in accordance with the present invention are shown inFormulae 3a-3f below; additional useful photosensitive materials areexemplified in U.S. Pat. No. 7,524,594 B2 columns 14-20 and areincorporated herein by reference:

Polymer composition embodiments of the present invention also includeadditives that are advantageously capable of bonding with the pendantacidic group of the resin. Such materials include, but are not limitedto, additives that incorporate one or more epoxy groups such as aglycidyl group, a epoxycyclohexyl group, an oxetane group; an oxazolinegroup such as 2-oxazoline-2-yl group, a methylol group such as aN-hydroxy methylaminocarbonyl group or an alkoxymethyl group such as aN-methoxy methylaminocarbonyl group. Generally, the aforementionedbonding with the pendant acid group of the polymer is a cross-linkingreaction that is initiated by heating to an appropriate temperature,generally above 110° C. for an appropriate amount of time.

Other exemplary cross-linking or crosslinkable materials that can beused as additives in the forming of a polymer composition embodiments ofthe present invention include, among others, bisphenol A epoxy resin,bisphenol F epoxy resin, silicone containing epoxy resins or the like,propylene glycol diglycidyl ether, polypropylene glycol diglycidylether, glycidyloxypropyltrimethoxysilane,polymethyl(glycidyloxypropyl)cyclohexane or the like; polymerscontaining oxazoline rings such as 2-methyl-2-oxazoline,2-ethyl-2-oxazoline, 1,3-bis(2-oxazoline-2-yl)benzene,1,4-bis(2-oxazoline-2-yl)benzene, 2,2′-bis(2-oxazoline),2,6-bis(4-isopropyl-2-oxazoline-2-yl)pyridine,2,6-bis(4-phenyl-2-oxazoline-2-yl)pyridine,2,2′-isopropylidenebis(4-phenyl-2-oxazoline),(S,S)-(−)-2,2′-isopropylidenebis(4-tert-butyl-2-oxazoline),poly(2-propenyl-2-oxazoline) or the like; N-methylolacrylamide,N-methylol methacrylamide, furfuryl alcohol, benzyl alcohol, salicylalcohol, 1,2-benzene dimethanol, 1,3-benzene dimethanol, 1,4-benzenedimethanol and resole type phenol resin or mixtures thereof. It has beenfound that, in general, such materials are effective at loadings from 5pphr polymer to 40 pphr polymer. However it should be understood thatloadings higher or lower may also prove effective as their efficacy isdependent, at least in part, on the nature of the polymer employed andits mole percent of repeat units encompassing crosslinkable pendentgroups.

For ease of understanding and without limitation, the followingexemplary structural representations of some additive materials usefulin embodiments of the present invention are provided hereinbelow withoutlimitation or restriction:

Polymer composition embodiments in accordance with the present inventionmay also encompass other components as may be useful for the purpose ofimproving the properties of both the composition and the resultingpolymer layer. For example the sensitivity of the composition to adesired wavelength of exposure radiation. Examples of such optionalcomponents include various additives such as dissolution promoters,surfactants, silane coupling agents and leveling agents.

To form polymer composition, or formulation embodiments of the presentinvention, the desired polymer and appropriate additives, as describedabove, are dissolved in a solvent to form a solution suitable forforming a film overlying a substrate. Useful solvents include, amongothers, N-methyl-2-pyrrolidone, y-butyrolactone, N,N-dimethylacetamide,dimethylsulfoxide, diethyleneglycol dimethylether, diethyleneglycoldiethylether, diethyleneglycol dibutylether, propyleneglycolmonomethylether, dipropylene glycol monomethylether, propyleneglycolmonomethylether acetate, methyl lactate, ethyl lactate, butyl lactate,methylethyl ketone, cyclohexanone, tetrahydrofuran,methyl-1,3-butyleneglycolacetate, 1,3-butyleneglycol-3-monomethylether,methyl pyruvate, ethyl pyruvate, methyl-3-methoxypropionate or mixturesthereof.

The photosensitive polymer composition embodiments, in accordance withthe present invention, are first applied to a desired substrate to forma film. Such a substrate includes any appropriate substrate as is, ormay be used for electrical, electronic or optoelectronic devices, forexample, a semiconductor substrate, a ceramic substrate, a glasssubstrate. With regard to said application, any appropriate coatingmethod can be employed, for example spin-coating, spraying, doctorblading, meniscus coating, ink jet coating and slot coating.

Next, the coated substrate is heated to facilitate the removal ofresidual casting solvent, for example to a temperature from 70° C. to130° C. for from 1 to 30 minutes, although other appropriatetemperatures and times can be used. After the heating, the film isgenerally imagewise exposed to an appropriate wavelength of actinicradiation, wavelength is generally selected based on the choice of thephotoactive compound and/or photosensitizer incorporated into thepolymer composition. However, generally such appropriate wavelength isfrom 200 to 700 nm. It will be understood that the phrase “imagewiseexposure” means exposing through a masking element to provide for aresulting pattern of exposed and unexposed portion of the film.

After an imagewise exposure of the film formed from polymer composition,or formulation, embodiments in accordance with the present invention, adevelopment process is employed. For the positive tone polymerformulations of the present invention, such development process removesonly exposed portions of the film thus leaving a positive image of themasking layer in the film. For the negative tone polymer formulations ofthe present invention, such development process removes only unexposedportions of the film thus leaving a negative image of the masking layerin the film. For some embodiments, a post exposure bake can be employedprior to the aforementioned development process.

Suitable developers, can include aqueous solutions of inorganic alkalissuch as sodium hydroxide, potassium hydroxide, sodium carbonate, ammoniawater and aqueous solutions of organic alkalis such as 0.26Ntetramethylammonium hydroxide (TMAH), ethylamine, triethylamine andtriethanolamine. Where an organic alkali is used, generally an organicsolvent essentially fully miscible with water is used to provideadequate solubility for the organic alkali. Aqueous solutions of TMAHare well known developer solutions in the semiconductor industry.Suitable developers can also include organic solvents such as PGMEA,2-heptanone, cyclohexanone, toluene, xylene, ethyl benzene, mesityleneand butyl acetate, among others.

Thus some formulation embodiments of the present invention provideself-imageable films that after imagewise exposure a resulting image isdeveloped using an aqueous base solution, while for other suchembodiments a resulting image is developed using an organic solvent.Regardless of which type of developer is employed, after the image isdeveloped, the substrate is rinsed to remove excess developer solution,typical rinse agents are water or appropriate alcohols and mixturesthereof.

After the aforementioned rinsing, the substrate is dried and the imagedfilm finally cured. That is to say, the image is fixed. Where theremaining layer has not been exposed during the imagewise exposure,image fixing is generally accomplished by causing a reaction within theremaining portions of the film. Such reaction is generally across-linking reaction that can be initiated by heating and/ornon-imagewise or blanket exposure of the remaining material. Suchexposure and heating can be in separate steps or combined as is foundappropriate for the specific use of the imaged film. The blanketexposure is generally performed using the same energy source as employedin the imagewise exposure although any appropriate energy source can beemployed. The heating is generally carried out at a temperature fromabove 110° C. for a time of from several minutes to one or more hours.Where the remaining layer has been exposed during the imagewiseexposure, image fixing is generally accomplished by a heating step totailored to complete any reaction initiated by the exposure. However anadditional blanket exposure and heating, as discussed above, can also beemployed. It should be realized, however, that the choice of a finalcure process is also a function of the type of device being formed; thusa final fixing of the image may not be a final cure where the remaininglayer is to be used as an adhesive layer or structure.

The devices are produced by using embodiments of the alkali solublephotosensitive resin composition of the present invention to form layerswhich are characterized as having high heat resistance, an appropriatewater absorption rate, high transparency, and low permittivity. Inaddition, such layers generally have an advantageous coefficient ofelasticity after curing, 0.1 kg/mm² to 200 kg/mm² being typical.

Embodiments in accordance with the present invention advantageously havea low modulus. Thus some embodiments of cured polymers, films, layers orstructures in accordance with the present invention have a modulus lessthan 3.0 GPa and as low as 0.3 GPa, others as low as 0.2 GPa, and stillothers as low as 0.1 GPa. As a skilled artisan knows, if the modulus istoo high, such a high modulus film will generally also have highinternal stress which can lead to reliability issues, e.g., die crackingor warpage in an electronics package.

As previously mentioned, exemplary applications for embodiments of thephotosensitive resin compositions in accordance with the presentinvention include die attach adhesive, wafer bonding adhesive,insulation films (interlayer dielectric layers), protecting films(passivation layers), mechanical buffer films (stress buffer layers) orflattening films for a variety of semiconductor devices, printed wiringboards. Specific applications of such embodiments encompass a die-attachadhesive to form a single or multilayer semiconductor device, dielectricfilm which is formed on a semiconductor device; a buffer coat film whichis formed on the passivation film; an interlayer insulation film whichis formed over a circuit formed on a semiconductor device.

Upon using the photosensitive resin composition of the invention forthese applications, the coefficient of elasticity of the resincomposition after curing is generally from 0.1 kg/mm² to 200 kg/mm², andoften from 0.1 kg/mm² to 100 kg/mm². Further, in such semiconductorapplications, a thickness of the layer of the photosensitive resincomposition after curing is generally from 0.1 μm to 200 μm, and oftenfrom 0.1 μm to 100 μm.

Embodiments in accordance with the present invention therefore provide apositive tone photosensitive polymer composition which exhibits enhancedcharacteristics with respect to one or more of mechanical properties(such as low-stress retained elongation to break after aging) and atleast equivalent chemical resistance, as compared to alternatematerials. In addition such embodiments provide generally excellentelectrical insulation, adhesion to the substrate, and the like. Thussemiconductor devices, device packages, and display devices are providedthat incorporate embodiments in accordance with the present invention.

EXAMPLES

Some of the following examples provide descriptions of polymerizationsof monomers that are useful for forming the polymer compositionembodiments of the present invention. It should be noted that while suchexamples may be used to prepare the polymers employed in the embodimentsof the present invention, they are presented only for illustrativepurposes and therefore are not limiting. Other examples presented hereinrelate to characteristics of the polymer and polymer compositionembodiments of the present invention. Such characteristics are ofinterest for enabling polymer design embodiments of the presentinvention as well as for demonstrating that such polymer and polymercomposition embodiments are useful.

Common to all polymerization examples that follow is that the reagentsused are essentially moisture and oxygen free (typically <10 ppm oxygenand <5 ppm H₂O). That is to say, that both the reagents and solvents arecharged into a reaction vessel and then sparged with nitrogen for aperiod of time believed sufficient to remove essentially all dissolvedoxygen, or the reagents and solvents are individually sparged prior totheir use and stored under a nitrogen blanket prior to being charged tothe reaction vessel. Therefore, it will be understood that while aspecific experimental description will not refer to either of the abovemethods of providing oxygen free reagents and solvents, one or the otherwas performed. Further, while not specifically mentioned in everyexample, an appropriate method of stirring or otherwise agitating thecontents of a reaction vessel was provided.

As used in the polymerization examples and throughout the specification,ratios of monomer to catalyst, and cocatalyst if present, are molarratios. Further, a number of acronyms or abbreviations are used in theexamples. To aid in the understanding of these examples and to simplifytheir presentation herein below, the following listing of such acronymsor abbreviations with their full meaning is provided in Tables 1A and1B:

TABLE 1A Additives 3-GTS (KBM-403E): (3-glycidyloxypropyl)trimethoxysilane [CAS: 2530-83-8] CGI-90:Octahydro-1-(phenylmethyl)-pyrrolo[1,2-a]pyrimidine [515145-31-0]Denacol EX321L:2,2′-(((2-ethyl-2-((oxiran-2-ylmethoxy)methyl)propane-1,3-diyl)bis(oxy))bis(methylene))bis(oxirane) SIB-1832:3,3,10,10-tetramethoxy-2,11-dioxa-3,10-disiladodecane CPTX:1-chloro-4-propoxy-9H-Thioxanthen-9-o Phenothiazine: 10H-PhenothiazineCHDVE: 1,4-Bis[(ethenyloxy)methyl]-cyclohexane Si-75:4,4,13,13-tetraethoxy-3,14-dioxa-8,9-dithia-4,13-disilahexadecaneAntioxidant 80 (AO80):2,2′-((2-hydroxy-5-methyl-1,3-phenylene)bis(methylene))bis(4-methylphenol) 4-PC:[2,2′-methylenebis[6-[(2-hydroxy-5-methylphenyl)methyl]-4-methyl-phenolLowinox 22M46: 6,6′-methylenebis(2-(tert-butyl)-4-methylphenol) Lowinox22IB46: 6,6′-(2-methylpropane-1,1-diyl)bis(2,4-dimethylphenol) Lowinox44B25: 4,4′-(2-methylpropane-1,1-diyl)bis(2-(tert-butyl)-5-methylphenol)Lowinox CA22:4,4′,4″-(butane-1,1,3-triyl)tris(2-(tert-butyl)-5-methylphenol) Irganox1010: PentaerythritolTetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) Naugard 445(NG445): bis(4-(2-phenylpropan-2-yl)phenyl)amine Steerer Star:bis(4-(tert-butyl)phenyl)amine Thermoflex: bis(4-methoxyphenyl)amineIrganox 5057: bis(4-(2,4,4-trimethylpentan-2-yl)phenyl)amine IrganoxL57: bis(4-(2,4,4-trimethylpentyl)phenyl)amine Wingstay 29::bis(4-(1-phenylethyl)phenyl)amine TrisP-3M6C-2(5)-201: Structure 3awhere 66% of Q is Structure 2a, the rest H TrisP-3M6C-2(4)-201:Structure 3a where 66% of Q is Structure 2b, the rest H Rhodorsil PI2074: tetrakis(2,3,4,5,6-pentafluorophenyl)borate(1-)[4-(1-methylethyl)phenyl](4-methylphenyl)-Iodonium

TABLE 1B Monomers HFANB2-(bicyclo[2.2.1]hept-5-en-2-ylmethyl)-1,1,1,3,3,3-hexafluoropropan-2-olTFSNB N-(bicyclo[2.2.1]hept-5-en-2-ylmethyl)-1,1,1-trifluoromethanesulfonamide NBnorbornene TESNB (bicyclo[2.2.1]hept-5-en-2-ylmethyl)triethoxysilaneMGENB 2-((bicyclo[2.2.1]hept-5-en-2-ylmethoxy)methyl)oxirane Acid NBbicyclo[2.2.1]hept-5-ene-2-carboxylic acid DecNB5-decylbicyclo[2.2.1]hept-2-ene PENB 5-phenethylbicyclo[2.2.1]hept-2-enePBNB 5-phenbutylbicyclo[2.2.1]hept-2-ene BuNB5-butylbicyclo[2.2.1]hept-2-ene EONB2-(6-(bicyclo[2.2.1]hept-5-en-2-yl)hexyl)oxirane NBCOOTMS trimethylsilylbicyclo[2.2.1]hept-5-ene-2-carboxylate EPEsNB ethyl3-(bicyclo[2.2.1]hept-2-en-2-yl)propanoate EPANB3-(bicyclo[2.2.1]hept-2-en-2-yl)propanoic acid AO2NB4,4′-(bicyclo[2.2.1]hept-5-en-2-ylmethylene)bis(2,6-di-tert-butylphenolNBMGlyHFP2-(2-(bicyclo[2.2.1]hept-5-en-2-yloxy)ethoxy)-1,1,1,3,3,3-hexafluoropropan-2-olNB-3-MPM 5-(3-methoxypropanoxy)methyl-2-norbornene NB-3-MBM5-(3-methoxypropanoxy)ethyl-2-norbornene NBTON5-((2-(2-methoxyethoxy)ethoxy)methyl)bicyclo[2.2.1]hept-2-ene NBTODD1-(bicyclo[2.2.1]hept-5-en-2-yl)-2,5,8,11-tetraoxadodecane NBEMHFPnorbornenyl ethoxymethylhexafluoropropanol NBMMHFP norbornenylmethoxymethylhexafluoropropanol

Monomer Synthesis Examples Example M1 Preparation of5-(3-methoxypropanoxy)methyl-2-norbornene (NB-3-MPM)

An appropriately sized and equipped reaction vessel was flushed with drynitrogen for 1 hour before use and then charged with toluene sulfonylchloride (TsCl) (159.3 g, 0.84 mol) and THF (370 ml, 291.4 g) to form areaction mixture. Two aliquots of a mixture of sodium-t-pentoxide (306.8g at 30% in THF) and 3-methoxy-1-propanol (53 g 0.59 mol) were added,drop wise, sequentially to the reaction mixture. When the temperaturereached 45° C. the reaction mixture was cooled with a water bath inorder to maintain the temperature in the range of 25° C. to 45° C. untilthe drop wise addition was complete. The chilling was then stopped andthe reaction mixture was stirred for an additional 1 hour, at 35° C.

Norbornene methanol (NBCH₂OH, 131.8 g 1.06 mol) was combined with asecond portion of sodium-t-pentoxide (306.8 g at 30% in THF) and addedto the reaction mixture. The reaction mixture was then heated to 45° C.and stirred for 18.5 hours after which time heating was stopped. Next,350 ml of water was added to the reaction mixture and the resultantmixture stirred for an additional 1.5 hours. The resulting monomer,86.47 g (54.0%) yield, was isolated after several washings and vacuumdistillation.

Example M2 Preparation of 5-(3-methoxypropanoxy)ethyl-2-norbornene(NB-3-MBM)

An appropriately sized and equipped reaction vessel was flushed with drynitrogen for 1 hour before use and then charged with toluene sulfonylchloride (111.1 g, 0.58 mol) and THF (824 ml, 732 g). A mixture ofsodium-t-pentoxide (76.4 g, 0.69 mol), THF (200 ml, 178.2 g) and3-methoxy-1-propanol (53 g, 0.59 mol) was added drop wise to thereaction mixture while monitoring the mixture's temperature. When thetemperature reached 45° C. the reaction mixture was chilled to maintainthe temperature in the range of 25° C. to 45° C. until the drop wiseaddition was complete. The ice bath was removed and the reaction wasallowed to stir without heating or cooling for an additional 1 hourafter which 53 ml of p-xylene was added and the mixture allowed to stirfor an additional 10 min.

Norbornene ethanol (NBCH₂CH₂OH, 76.68 g 0.56 mol) was combined with asecond portion of sodium-t-pentoxide (306.8 g at 30% in THF) and addedto the reaction mixture. The reaction mixture was then heated to 50° C.and stirred for 18.5 hours after which heating was stopped. Next, 250 mlof water were added to the reaction mixture and the resultant mixturewas stirred for 1.5 hours. The resulting monomer, 75 g, 64.3% yield, wasisolated after several washings and vacuum distillation.

Polymerization Examples Example P1 70/30 NBTON/MGENB

An appropriate sized reaction vessel was dried and purged with N₂ tominimize air and water contamination. The vessel was then charged with:1,189.1 g of Toluene, 65.6 g of MEK, 245.6 g of NBTON (1.09 moles) and83.8 g of MGENB (0.47 moles). The reaction medium was purged of oxygenby passing a stream of dry N₂ through the solution for 30 minutes whileheating to 45° C. After the purge was complete, 6.26 g (0.013 mol) of(toluene)bis(pentafluorophenyl)nickel (NiArf) dissolved in 56.4 g oftoluene was injected into the reaction vessel. The reactor temperaturewas increased to 60° C. at a rate of 1° C. per minute and the reactionmixture was stirred for three hours.

The polymerization reaction was terminated by the addition of 5 g waterto the reaction mixture. Unreacted monomer was removed by extracting thereaction solution with two solvent washes comprising a mixture ofultrapure water (10 g), methanol (49 g) and heptanes (1647 g). Aftereach solvent extraction, the mixing was stopped, the resulting phaseswere allowed to separate and the top phase was decanted. The solventcomposition of the polymer phase was kept constant in each of thesolvent extractions. The polymer was dissolved in 1086.8 g of1,3-dioxolane. Two acidifications followed consisting of 231.4 g 30%hydrogen peroxide, 123 g acetic acid, and 1482 g water. Eachacidification was run for 30 minutes at 50° C. After each acidificationthe mixing was stopped, the solution allowed to separate, and the bottomphase is decanted. Again solvent ratios were kept constant in each ofthe acidifications. The last acidification was followed by 3 waterwashes consisting of 329.3 g methanol and 1811.3 g ultra pure (UP)water. The water washes were mixed for 15 minutes at 50° C. After eachwaster wash, the mixing was stopped, the solution allowed to separate,and the bottom phase is decanted. 345.8 g of THF were added to thesecond and third water wash it assist the separation. Finally thepolymer was diluted in MAK the residual solvents were stripped on arotovap.

The above procedure was repeated twice to form the polymers of ExamplesP2 and P3 and used as a template for the formation of Examples P4-P8.The composition of each of Examples P1-P8, the % conversion and finalM_(w) and PDI are provided in Table 2, below:

TABLE 2 Data for Solvent Develop Polymer Compositions Ex. % #COMPOSITION Conversion Mw PDI P1 70/30 NBTON/MGENB 96.5% 67,600 1.88 P280/20 NBTON/MGENB 96.9% 72,000 2.12 P3 90/10 NBTON/MGENB 95.7% 66,5001.72 P4 50/20/30 NBTON/PENB/MGENB 99.6% 73,800 1.89 P5 20/50/30NBTON/DecNB/MGENB 98.0% 78,000 2.47 P6 40/30/30 NBTON/DecNB/MGENB 90.9%66,500 1.95 P7 80/20 NBTON/EONB 67.0% 64,100 1.65 P8 30/40/30NBTODD/PENB/MGENB 98.3% 90,800 1.95

Examples P9-P12 45/15/40 HFANB/NBEtCOOH/NBTON: Polymer Example P9

A polymer encompassing repeat units derived from HFANB, EPEsNB and NBTONwas prepared as follows: An appropriate sized reaction vessel was driedand purged with N₂ to minimize air and water contamination. The vesselwas then charged with: toluene (992 g), DME (116 g), HFANB (148 g, 0.54mol), EPEsNB (20.7 g, 0.11 mol) and NBTON (61.9 g, 0.27 mol). Thereaction medium was purged of oxygen by passing a stream of dry N₂through the solution for 30 minutes while heating to 45° C. In aseparate vessel, additional EPEsNB (14.2 g, 0.073 mol) and NBTON (46.7g, 0.16 mol), for metering into the reaction vessel, were combined andpurged with N₂. After the purging was completed, 5.82 g (0.012 mol) ofbis(toluene)bis(perfluorophenyl)nickel (NiArf) dissolved in 60.5 ml oftoluene was injected into the reaction vessel containing all threemonomers. Simultaneously, the metered feed portion of the monomers wasadded at a rate intended to keep unreacted monomers at a constant levelfor the duration of the polymerization (3 h).

Any unreacted monomers were removed and the resulting polymer dissolvedin methanol/THF (approximately 1 L total volume in a 4/5 ratio). Theester functionality was hydrolyzed using NaOH solution at a ratio of4.8/1 NaOH/NaOAc for 4 hours at 60° C. Two acidifications followedconsisting of 405 g methanol, 196 g THF, 87 g acetic acid, 67 g formicacid, and 21 g water. Each acidification was run for 15 minutes at 50°C. After each acidification the mixing was stopped and the solutionallowed to separate, and the top phase is decanted. This is followed bythree water washes consisting of 390 g methanol and 2376 g water for ˜15minutes at 60° C. The solvent ratios were kept constant in each of thewater washes. Finally the polymer was diluted in its final solvent andsent for solvent exchange. Conversion: 93.1%; M_(w)=85,900, PD=2.52.

Polymer Examples P10-P14 were prepared using the method of PolymerExample P9 as a template. Specific polymerization details are presentedin the Table 3, below, where monomers A, B, C, D, E and F are HFANB,EPEsNB, NBCOOTMS, NBTON, NB-3-MPM and AO2NB, respectively. It should benoted that as described above the ester functionality of the repeatunits derived from ester containing EPEsNB monomer are hydrolyzed suchthat the final polymer only has an acid functionality. M_(w) ispresented in atomic mass units (amu).

TABLE 3 Data for Aqueous Base Develop Polymers P9-P14 PolymerComposition (mol %) Conversion M_(w) Polymer A B C D E F (%) (amu.) PDIP9  46 15 39 — 93.1 85.9 K 2.52 P10 39 13 48 — 86.0 67.4 K 2.52 P11 2525 50 — 91.2 75.6 K 1.74 P12 54 14 30 2 89.0 76.9 K 1.86 P13 30 20 5070% 57.4 K 1.87 P14 45 15 40 92%  102 K 2.03

Formulation Examples CIS/RDL Formulations

The following formulations are appropriate for polymers P1-P8 in Table2.

Examples F1-F8

A series of 55 wt % solutions (F1-F8, shown in Table 4, below) ofpolymer P2 in MAK (F1) or PGMEA (F2-F8) having the specific amounts ofadditives, expressed as parts per hundred resion (pphr) (Rhodorsil PI2074, CPTX, phenothiazine, Si-75, AO-80 and Naugard 445) were mixed inan appropriately sized amber HDPE bottle with an appropriate amount ofMAK for F1 and PGMEA for F2-F8. The mixture was rolled for 18 hours toproduce a homogeneous solution. Particle contamination was removed byfiltering the polymer solution through a 1 μm pore nylon disc filterunder 35 psi pressure, the filtered polymer solution was collected a lowparticle HDPE amber bottle and the resulting solution stored at 5° C.

TABLE 4 Solvent developable photoactive formulations Formulation F1 F2F3 F4 F5 F6 F7 F8 Rhodorsil PI 5.6 2 2 2.8 2.8 5.6 2 2074 GSID-26-1 2CPTX 1.2 0.6 — 0.6 0.6 0.6 1.2 0.6 Phenothiazine 0.36 0.14 0.14 0.140.18 0.18 0.36 0.14 Cyclohexane 5 Divinyl Ether Antioxidant 80 5 5 5 5 55 5 Irganox 1076 1.5 Naugard 445 5 5 5 5 5 5 KBM-403E 5 5 5 2.5 5 5Si-75 3 3 3 3 3 2.5 3 SIB-1832 10 5 10

ChipStack/RDL Aqueous Base (0.26N TMAH) Develop Formulations

Formulation F9: A 57.3 weight % solution of polymer P1 in PGMEA (31.3g), TrisP-3M6C-2(5)-201 (3.10 g), BY-1,6-15 (1.86 g), SIB-1832 (1.25 g),Denacol EX-321L (0.62 g), Si-75 (0.38 g), Naugard 445 (1.24 g), AO-80(0.81 g) and PGMEA (9.82 g) were mixed in an appropriately sized amberHDPE bottle. The mixture was rolled for 16 hours to produce ahomogeneous solution. Particle contamination was removed by filteringthe polymer solution through a 0.2 μm pore PTFE disc filter under 35 psipressure, the filtered polymer solution was collected a low particleHDPE amber bottle and the resulting solution stored at −5° C.

The above procedure was repeated using TrisP-3M6C-2(4)-201 to formFormulation F10 and this procedure was used as a template to makeformulations F11-F16, each of which include an additional 10 pphr of theexperimental hindered phenol compound indicated. Each of such hinderedphenol additives being distinct from one another and represented byStructural Formula II:

where R¹⁰ is methylene or a C₂-C₁₂ substituted or unsubstituted alkyleneor cycloalkylene, R¹², if present, is a C₁-C₁₂ substituted orunsubstituted alkyl, and m is independently either 0, 1 or 2.

As will be discussed below, these formulations were evaluated withregard to image threshold energy to determine the impact, if any, thatthe experimental hindered phenols (EHPs) exhibited.

TABLE 5 Aqueous Base Developable Photoactive Formulations Formulation F9F10 F11 F12 F13 F14 F15 F16 TrisP-3M6C-2(5)- 25 201 TrisP-3M6C-2(4)- 2525 25 25 25 25 25 201 BY-16-115 15 15 15 15 15 15 15 15 Denacol-EX321L 55 5 5 5 5 5 5 SIB-1832 10 10 10 10 10 10 10 10 Si-75 3 3 3 3 3 3 3 3Naugard 445 10 10 10 10 10 10 10 10 AO-80 6.5 6.5 6.5 6.5 6.5 6.5 6.56.5 EHP 1 10 EHP 2 10 EHP 3 10 EHP 4 10 EHP 5 10 EHP 6 10

Characterization Data

Threshold Energy (Eth) Measurement

Formulations F9-F16 were each applied to a 200 mm diameter silicon wafer(thickness: 725 μm) by spin coating. The substrate was then placed on a100° C. hot plate for 300 seconds, providing a film about 10 μm thickpolymer film. Each polymer film was then imagewise exposed through usinga range of exposure energies from 50-730 mJ/cm². Each film was thendeveloped using a puddle development method having two 30 secondimmersions in 0.26N TMAH. After the develop process each wafer wasrinsed by spraying deionized water for 5 seconds and then dried byspinning at 3000 rpm for 15 seconds. Each film was then evaluated todetermine the threshold energy required to give a 100 μm square viahole. The specific compositions of formulations F9-F16 is provided inTable 5 above. As seen in Table 5A, below, each of Formulations F11-F13and F16 exhibited a lower threshold energy than formulation F10, thusdemonstrating that some of the experimental hindered phenol additivesimproved the observed sensitivity of the imageable polymer film.

Measured E_(th) values for formulations F10-F16 are summarized in Table5A below.

TABLE 5A Measured E_(th) Values Formulation Thickness Loss Eth (100 μmvia) F10 0.00 320 F11 0.04 300 F12 0.02 290 F13 0.04 280 F14 0.02 330F15 0.05 330 F16 0.05 280

Water Vapor Transmission Rate (WVTR)

Water vapor transmission data were collected following ASTM E96,Procedure B (water and desiccant) as follows. Approximately 100 mL ofdeionized water was added to each water vapor transmission fixture suchthat the level was within ¼″ of where the test specimen would belocated. Each test specimen was then mounted onto a fixture and securedusing the knurled set screws and gasket

All of the fixtures were then initially weighed to the nearest 0.01 gand placed into a temperature/humidity chamber maintained at 23° C. and50% relative humidity (R.H.). Once the first fixture was placed into thechamber, a stopwatch was started to monitor each test specimen'sexposure time. The elapsed time was then recorded for each additionalfixture added to the chamber. At periodic intervals, each fixture wasremoved from the chamber and once again weighed to the nearest 0.01 g.The elapsed time was also recorded and the fixture was placed back inthe chamber. Typically, an overall weight change for the material undertest equivalent to 100 times the balance sensitivity is desired. TheWater Vapor Transmission (WVT) value for each test specimen wascalculated using the slope of the plotted data points and the followingequation:

WVT=(G/t)1/A

where G=weight change, in grams; t=elapsed time in which G has occurred,in hours; (G/t)=slope of the straight regression line, g/hr or g/day;and A=sample test area, in square meters.

A free-standing, 110-140 μm thick film of polymer formulation F2 wasprepared as follows: 100 g of the formulation F2 was poured onto a glassplate (14″×8.5″) wide and drawn into a uniform layer using a filmcasting knife (BYK-Gardner PAG-4340) with a gap height of 0.025 inches.The films were dried for 72 hours at ambient temperature and thenexposed to 1 J/cm² of broad band UV radiation and cured at 180° C. undera nitrogen atmosphere for 120 minutes. The cured films were lifted fromthe glass substrate by immersion in a 1 weight % aqueous HF bath for 18hours and then dried in air for 24 hours. The water vapor transmissionrate of the polymer film was measured by ASTM E96 Procedure B (water anddesiccant) at 23° C. and 50% Relative humidity for 7 days. The film wasfound to have a water vapor transmission rate of 141.2 gram/squaremeter/day.

TABLE 6 Water Vapor Transmission Rate Formulation Film thickness (μm)WVTR (g/m²/day) F2 132 141.2 F3 127 160.1 F4 119 142.8 F5 127 135.8 F6123 45.6 F7 123 32.6 F8 125 191 F9 118 17.4 Avatrel 2580-40 136 19.6

Sample Preparation for Isothermal TGA Analysis

A series of formulations, F18-F30, were prepared in order to confirm theefficacy of the NG445 additive as a stabilizer during the thermal cureof the NBTON repeat unit side chain in, for example polymers P1 and P2copolymers. Formulation examples were prepared in the manner describedabove for formulations F10-F16 but where Formulations F18-F24 includepolymer P1 and formulations F25-31 include polymer P2. And further, foreach formulation, the amount of each additive included in eachformulation is indicated in Table 7 below.

After forming, for each formulation a 4 mL aliquot was spin coated ontoa 125 mm Si wafer at 750 rpm for 30 seconds using a CEE 100CBX spincoating station. The film was dried by baking on a hot plate at 100° C.for 4 minutes. The film was exposed to a 1 J/cm² blanket exposure of 365nm UV light and post exposure baked on a hot plate for 5 minutes at 90°C. A portion of each film was removed from the wafer, placed in aplatinum thermal analysis pan (TA) and weighed. The portion was thenbaked at 180° C. for 2 hours under a nitrogen atmosphere in a TA Q500TGA Thermogravimetric Analyzer. The percent weight (wt %) loss of eachportion is reported in Table 7, below. As it can be seen, for sampleswithout the photoacid Rhodorsil, or samples with such photoacid andNG-445, weight loss is minimal. However, absent NG-445, the weight lossis significant for each of the two polymers. Without wishing to be boundby theory, the apparent enhanced stability of the P2 samples is believedto be the result of the higher mol % of NBTON, as compared to P1,cross-linking more efficiently. While formulations F24 and F31 areanalogous to formulations F 19 and F26 in that they do not containNG-445 but do contain a strong acid (Pyridinium Triflate rather thanRhodorsil) it is believed that the lower weight loss seen, for exampleF19 21.38% versus F24 1.87%, is indicative of Rhodorsil being asignificantly stronger acid than pyridinium triflate.

TABLE 7 Thermal Stability of NBTON/MGENB Polymers (NG-445) PyridiniumWeight Ex. # Rhodorsil Triflate CPTX NG-445 AO-80 Loss F18 0 0 0 0 00.41 F19 0.33 0 0 0 0 21.38 F20 0.33 0 0.1 0 0 21.89 F21 0.33 0 0.1 0.830 0.55 F22 0.33 0 0.1 0 0.83 21.3 F23 0.33 0 0.1 0.83 0.83 0.69 F24 00.33 0 0 0 1.87 F25 0 0 0 0 0 1.99 F26 0.33 0 0 0 0 16.72 F27 0.33 0 0.10 0 15.47 F28 0.33 0 0.1 0.83 0 0.9 F29 0.33 0 0.1 0 0.83 15.09 F30 0.330 0.1 0.83 0.83 1.14 F31 0 0.33 0 0 0 3.15

Sample Preparation for DMA and Tensile Testing (Mechanical PropertyTesting)

Formulations F32-F43 were prepared in the manner described forFormulation F1, above. The specific base polymer and formulation foreach of the examples is shown in Table 8.

TABLE 8 Formulations for DMA Testing Base Formulation FormulationPolymer Recipe F32 P2 F5 F33 P2 F6 F34 P3 F7 F35 P3 F5 F36 P1 F2 F37 P2F2 F38 P1 F2 F39 P2 F2 F40 P2 F3 F41 P7 F2 F42 P6 F2 F43 P4 F2

An 8 mL aliquot of each of formulations F32-F43 was spin cast onto aseries of 125 mm Si wafers at 420 rpm for 90 seconds using a CEE 100CBXspin coating station. The films were dried by baking on a hot plate inproximity mode at 100° C. for 10 minutes. Each dried film was thenexposed to a 1 J/cm² blanket exposure of 365 nm UV light and postexposure baked on a hot plate for 10 minutes at 90° C. Each wafer wasthen additionally heated in a Despatch LAC High Performance Oven at 180°C. under a nitrogen atmosphere for 120 minutes to complete thecrosslinking of the pendant epoxide functional groups. Each Si wafer wasdiced in to 10 mm wide strips and the polymer film on each strip liftedby immersion in a 1% aqueous HF bath at ambient temperature forapproximately 24 hours, after which the strips were dried in air for 24hours before testing.

The tensile properties of each sample was tested using an Instron 5564Dual Column Tensile Tester with a rate of sample elongation of 5nanometers (nm) per second at ambient temperature.

Dynamic Mechanical Analysis (DMA) was performed on a TA Instruments Q800DMA over a temperature range of −75° C. to 250° C. at a heating rate of2° C./minute with a sample strain amplitude of 15 μm and a frequency of1.0 Hz. The CTE was reported as the slope of the curve between 140° C.and 180° C. Modulus and tensile strength are reported in Table 8 asgigaPascals (GPa) and megaPascals (MPa), respectively, while elongationto break is reported as a percentage and the transition temperatures inTable 9 as degrees Celsius.

TABLE 9a Tensile Properties for Formulations F32-F43 Formulation ModulusTensile strength Elongation to Break F32 1.39 31.9 9.5 F33 0.37 10.220.6 F34 0.21 6.4 26.0 F35 1.50 38.4 21.6 F36 0.8 17.8 15.9 F37 0.3610.8 22.9 F38 0.73 16.5 14.3 F39 0.39 10.3 18.1 F40 0.31 9.9 21.6 F410.29 8.2 10.4 F42 0.52 11.7 12.9 F43 1.88 34.4 6.9

TABLE 9b Dynamic Mechanical Analysis Transition Temperatures Transition#1 Transition #2 Formulation β Transition (° C.) Tg (° C.) F32 −42.3 144.5 F33 21.9 59.6 F34 — 27.1 F35 −54.6  154.0 F36 42.1 74.6 F37 21.361.0 F38 39.4 77.9 F39 * 64.3 F40 * 67.13 F41 20.3 58.5 F42 — 73.4 F4376.9 118.2

Oxidative Stability of Aqueous Avatrel

For Formulation Examples F44 through F53 the polymer compositionencompassed polymer P9 dissolved in a PGMEA carrier solvent. ForFormulation Examples F55 and F56 the polymer composition encompassedpolymer P14 dissolved in a PGMEA carrier solvent. Formulations F48through F52 are polymer compositions that encompass P9, AO-80, and thediarylamines shown in Table 11.

Formulation F54 encompasses P9 with Naugard-445 and the antioxidant 4-PC[2,2′-methylenebis[6-[(2-hydroxy-5-methylphenyl)methyl]-4-methyl-phenol(CAS #20837-68-7)] in place of AO-80.

Each of the formulations shown in Table 11 encompasses each of theadditives shown in Table 10. The amount of each additive employed ispresented in parts per hundred (pphr) polymer and is therefore based onthe polymer (pphr) loading.

TABLE 10 Base Polymer Composition Formulation Amount Formulation (pphrpolymer) Polymer P9 TrisP-3M6C-2(5)-201 25 BY-16-115 15 Denacol-EX321L 5SIB-1832 10 Si-75 3

In addition to the additives shown in Table 10, each formulationincludes a phenolic antioxidant (AO) and a diaryl amine synergist (DAS).The lithographic, speed and resolution of formulations F44 through F56are shown in Table 11, below. It should be noted that the phenolicantioxidant employed was AO-80 for all formulations except for F52 andF54, where 4-PC and Irganox 1010 were used, respectively. With regard tothe diarylamine synergist, NG-445 was employed for all formulationsexcept for F48, F49, F50 and F51 where 4,4′-di-tert-butyl diphenylamine,Irganox 5057, Thermoflex and Agerite White were used, respectively.Furthermore, all additive loadings are expressed as parts per hundredresin (pphr), photospeed is expressed as millijoules per centimetersquared (mJ/cm²) and resolution is of a line and space structure andexpressed as micrometers (μm). All of the formulations were preparedusing the procedure presented above for Formulation F1 but where thespecific materials and loadings are presented in Tables 10 and 11, aboveand below. Therefore it will be understood that the preparation ofFormulation F3 is for illustrative purposes only.

TABLE 11 Screening Antioxidants for Photospeed and Resolution Ex. AO DASLithography # Polymer Loading Loading Photospeed Resolution F44 P9 0 0404 7 F45 P9 10 0 404 7 F46 P9 6.5 10 404 7 F47 P9 10 10 404 7 F48 P96.5 10 404 10 F49 P9 10 10 404 10 F50 P9 10 10 404 25 F51 P9 10 10 404 5F52 P9 6.5 10 404 10 F53 P12 0 0 976 100 F54 P12 10 0 976 100 F55 P14 00 976 100 F56 P14 10 10 976 100

An optimization of the formulation additives to balance improvedoxidative stability and photolithography properties was completed.Formulations F57 to F68, made using polymer P9, are listed in Table 12below.

A series of silicon wafers were coated with a thick film of each ofpolymer formulations F57-F68 and then blanket exposed to 1 J/cm² dose of365 nm UV light. After exposure, each wafer was baked in a Despatch LACHigh Performance Oven at a 180° C. under a nitrogen atmosphere for 120minutes to complete the crosslinking of the multifunctional epoxideformulation additives Denacol EX-321L, BY16-115, TrisP-3M6C-2(5)-201 andSIB-1832.

The wafers were then placed in a Lindburg Blue-M oven heated at 150° C.for up to 200 hours in an air atmosphere. Each wafer was diced into 10mm wide strips and the polymer film lifted from the strips by immersionin a 1% aqueous HF bath at ambient temperature. Each film was dried inair for 24 hours and the tensile properties tested using an Instron 5564Dual Column Tensile Tester. The test results being shown in FIGS. 3-5 asnormalized values to allow an optimized formation to be selected.

Thermo-oxidative degradation of a PNB polymer is accompanied by the lossof elongation to break due to (a) the loss of the polyether functionalsidechain or (b) further crosslinking of the polymer film.

TABLE 12 Optimization of Antioxidant Package in P9 Formulation AdditiveLoading (pphr) Ex. Si- NG- AO- BY16- SIB- # 75 445 80 22M46 †† 115 **1832 F57 8.23 8.27 3.00 25 15 5 10 F58 5.44 10.00 4.06 25 15 5 10 F5910.00 5.38 4.12 25 15 5 10 F60 10.00 3.00 6.50 25 15 5 10 F61 3.00 10.006.50 25 15 5 10 F62 6.36 6.37 6.77 25 15 5 10 F63 7.63 4.11 7.76 25 15 510 F64 6.50 3.00 10.00 25 15 5 10 F65 3.00 6.50 10.00 25 15 5 10 F666.36 6.37 0.00 6.77 25 15 5 10 F67 6.36 6.37 6.77 25 15 5 0.00 F68 10.0010.00 10.00 25 15 5 10 †† TrisP-3M6C-2(5)-201 ** Denacol EX-321L

Device Build Examples

CIS Cavity Package

A 125 mm SiO₂ wafer was placed in a March CS-1701 reactive ion etch (RIEtool) and the surface was cleaned with a mixed oxygen-argon plasma (300mtorr, 300 W, 30 seconds). An 8 mL aliquot of formulation F37 was spincast onto a 125 mm Si wafer (625 μm thick) at 1200 rpm for 60 secondsand then at 3000 rpm for 10 seconds using a CEE 100CBX spin coatingstation. The film was dried by baking on a hot plate in proximity modeat 100° C. for 5 minutes. The polymer film was imagewise exposed througha negative tone mask with a grid pattern of 500 μm square via openingsto a 780 mJ/cm² dose of 365 nm UV light and then baked on a hot platefor a further 4 minutes at 90° C. The unexposed portion of the polymerfilm was developed by spraying with MAK solvent for 21 seconds onto thewafer as it was spinning at 150 rpm. The polymer film was then rinsedwith a spray of isopropanol for 5 seconds. The polymer film was dried inair for 18 hours.

A 125 mm borofloat glass wafer (350 μm thick) was placed in a MarchCS-1701 reactive ion etch (RIE tool) and the surface was cleaned with amixed oxygen-argon plasma (300 mtorr, 300 W, 30 seconds). The treatedsurface of the glass wafer was placed in contact with the polymer filmon the glass wafer and the wafer stack was placed into a Suss Bonderwhich had been preheated to 90° C. The tool was sealed and the chamberevacuated to 5×10⁻⁴ mbar and then the sample was heated to 110° C. at arate of 10° C. per minute. The bonding pressure was raised to 1 MPa for3 minutes in order to create a thermo-compression bond between thepolymer dam and the glass wafer. The pressure was released and thesample was cooled to 90° C. before removal from the bonder. The waferswere baked in a Despatch LAC High Performance Oven a temperature of 180°C. under a nitrogen atmosphere for 120 minutes to complete thecrosslinking of the pendant epoxide functional groups and developchemical bonding of the polymer to the wafer substrates.

Alternate Bonding Condition

A 100 mm glass wafer was pretreated with Piranha solution cleaned for 15minutes, then rinsed with deionized water and dried before bonding. A125 mm Si wafer coated with a 50 μm thick polymer dam was placed on thebottom chuck of the EVG 501 bonder. The 4″ glass wafer was placed on topof the 5″ coated wafer and a 20 N force was applied to prevent glasswafer from shifting. The chamber was cycled 3 times with vacuum followedby nitrogen purge. The tool was sealed and chamber was evacuated. Thebonding force of 6000 N (bonding pressure about 1.0 MPa) was applied.The temperature was ramped to 200° C. for both top and bottom chucks.The 6000 N bond force and 200° C. bond temperature were maintained for30 minutes. The chamber was cooled to room temperature, pressure wasreleased and wafer was unloaded. The bonded wafer was cured at 180° C.for 120 minutes under nitrogen.

Comparative Example

A 125 mm SiO₂ wafer was placed in a March CS-1701 reactive ion etch (RIEtool) and the surface was cleaned with a mixed oxygen-argon plasma (300mtorr, 300 W, 30 seconds). An 8 mL aliquot of a commercially availableepoxide adhesive was spin cast onto a 125 mm Si wafer (625 μm thick) at1600 rpm for 30 seconds using a CEE 100CBX spin coating station. Theedge-bead was removed using a 15 second PGMEA spray. The film was driedby baking on a hot plate in proximity mode at 80° C. for 2 minutes. Thepolymer film was imagewise exposed through a negative tone mask with agrid pattern of 500 μm square via openings to a 250 mJ/cm² dose of 365nm UV light and then baked on a hot plate for a further 2 minutes at 90°C. The unexposed portion of the polymer film was developed by immersingthe wafer in a bath of PGMEA solvent for 5 minutes with slightagitation. The polymer film was then rinsed with a spray of isopropanolfor 5 seconds. The polymer film was dried in air for 18 hours.

A 125 mm glass wafer (350 μm thick) was placed in a March CS-1701reactive ion etch (RIE tool) and the surface was cleaned with a mixedoxygen-argon plasma (300 mtorr, 300 W, 30 seconds). The treated surfaceof the glass wafer was placed in contact with the polymer film on theglass wafer and the wafer stack was placed into a Suss Bonder at ambienttemperature. The tool was sealed and the chamber evacuated to 5×10⁻⁴mbar and then the sample was heated to 110° C. at a rate of 10° C. perminute. The bonding pressure was raised to 1 MPa for 3 minutes in orderto create a thermo-compression bond between the polymer dam and theglass wafer. The pressure was released and the sample was cooled toambient temperature before removal from the bonder. The wafers werebaked in a Despatch LAC High Performance Oven a temperature of 180° C.under a nitrogen atmosphere for 120 minutes to complete the crosslinkingof the pendant epoxide functional groups and develop chemical bonding ofthe polymer to the wafer substrates.

The bonded glass to wafer stack was then subjected to hightemperature/high humidity 85° C./85% RH for 168 hours. Visual inspectionof the encapsulated cavities using a Nikon OPTIPHOT-88 microscopeimmediately after removal from the ESPEC Temperature and HumidityChamber SH-240 indicated whether fog or water droplets condensed in thecavities. The fog test reliability results are presented in Table 13below. As it can be seen, CIS dam structures formed from polymercomposition embodiments in accordance with the present inventionoutperform the commercially available epoxide adhesive under highhumidity conditions.

TABLE 13 Results of Fog Testing 168 hours @ Formulation 85° C./85% RHF39 No Fog F40 No Fog F41 No Fog F42 No Fog F43 No Fog ComparativeMaterial Fog

Chip Stack Device Fabrication

Formulation F9 was applied to a 200 mm diameter silicon wafer(thickness: 725 μm) by spin coating. The substrate was then placed on a100° C. hot plate for 300 seconds providing a nominally 11.0 μm thickpolymer film. Thereafter, the resin layer was subjected to a floodexposure at an exposure intensity of 25 mW/cm² for 40 seconds using aMA-8 mask aligner (Suss Microtec AG) without a masking element. Afterthe flood exposure, the wafers were baked on a hot plate at 150° C. for10 min.

Then, non-photosensitive type back grinding tape was laminated on theresin layer of the wafer, and the backside of the wafer opposite theresin layer was ground and dry polished to thin the silicon layer of thewafer to 50 μm thick. The back-grinding tape was subsequently removed.

Next, dicing tape was laminated on the backside surface of the wafer,and the wafer was cut by a dicing saw (DAD341, DISCO corp.) into 7 mmsquares to obtain thinned silicon chips having a resin layer.

In parallel, dicing die-attach tape (IBF-8550C, Sumitomo Bakelite Co.,Ltd.) was laminated to the backside surface of a second thinned wafercoated with the polymer adhesive layer on the opposite side. The waferwas then diced with the manner described above to obtain similar 7 mmsquare silicon chips.

Onto a bismaleimide-triazine resin laminate board substrate (thickness:0.35 mm) coated with a 20 μm±5 μm thick layer of solder resist (PSR4000AUS308, Taiyo Ink Mfg.) was mounted die containing the adhesion layerfrom the dicing die-attach tape. The chips were mounted (tape-side down,resin-side up) at a temperature of 130° C. and a pressure of 10 N for 2seconds by using a chip placement tool BESTEM-D02 (Canon Machinery). Ontop of the mounted chip, another chip diced from the wafer without usingdicing die-attach tape (i.e. without adhesion layer on ground surface)was bonded resin-side up at a temperature of 150° C. and a pressure of10 N for 1 sec using the same apparatus to make chip stacked structureon a substrate. The stacked chip package substrate was heated at 175° C.for 15 minutes to approximate the thermal history of gold wire-bonding.

Then, the surface of the substrate mounted with the stacked chips wasencapsulated with an encapsulating resin (EME-G760L, Sumitomo BakeliteCo., Ltd.) by transfer molding at a temperature of 175° C. and apressure of 10 N for 1 minute by using a molding machine (Y1E, TOWA Co.,Ltd.). The overmolded package on board containing multiple die stackswas then subjected to a heat treatment of 175° C. for 4 hours to cureboth the coated resin layer and the encapsulating molding compound tothereby obtain semiconductor devices.

Nine semiconductor devices were selected from the aforementionedprocess. The devices were treated at a temperature of 85° C. and ahumidity of 60% RH for 168 hours in an ESPEC Temperature & HumidityChamber LHL-113; thereafter, they were passed through a reflow furnaceat a temperature of 260° C. three times. Each of the semiconductordevices was investigated with respect to scanning acoustic tomography(SAT) measurement and cross-sectional observation after the reflowprocess. The examination of the semiconductor devices found no defectsor interlayer delamination failures had occurred in any of the packages.In a separate set of 7 semiconductor devices from the same process, thedevices were subjected to thermal-cycling conditions (−55° C.+125° C.,1000-cycle). No voids were detected via SAT or cross-sectionalobservation after thermal-cycling. Thus, it can be seen that polymercomposition embodiments in accordance with the present invention canprovide chip stack devices that both perform well under high humidityand through thermal cycling.

RDL Device Fabrication

Redistribution layer devices were prepared using formulation F9 and twocommercially available comparative polymers Comparative Polymer 1 (CP1)and Comparative Polymer 2 (CP2). A total of three device wafers wereprepared for each resin. The accumulated data for the devices appearsbelow in Table 14. In the table, soft bake (SB), post expose bake (PEB)and cure data provides temperatures expressed in ° C. and time inminutes, exposure in mJ/cm² and resistance in ohms.

A series of 6″ silicon wafers, each deposited with 2000 Å of PECVDnitride and 2000 Å of sputtered copper were spin-coated (˜1 μm) withShipley 1813 positive-tone photoresist and then soft baked on a hotplateat 110° C. for 3 minutes. The coated wafer was subjected to actinicradiation (90 mJ/cm², i-line) through a photomask. The features weredeveloped in 0.26 N TMAH (Rohm & Haas, CD 26). After hard-baking (130°C., 3 min), the exposed copper metal in the developed areas was etchedusing copper etchant (Transene APS-100) to reveal two copper pads (75 μmdiameter) connected by a copper trace (25 μm width). After deionized(DI) water rinse, the undeveloped photoresist was removed using acetone.

Each wafer having the patterned first copper traces was then subjectedto reactive ion etch (25/19 sccm Ar/O₂, 300 W, 300 mtorr, 30 sec),spin-coated with one of Formulation F9, CP1 or CP2 and soft baked asindicated in Table 14. After soft bake, each layer was imagewise exposedthrough a masking element on an mask aligner through an i-line band passfilter to the exposure dose indicated in Table 14 for that formulation.Also as shown in Table 14, the CPI wafers received a post exposure bakeand were then joined with the other wafers for development of the latentpattern by spraying with 0.26 N TMAH aqueous developer to reveal 50 μmdiameter via openings over pad portions of the first copper traces. Eachpatterned wafer was then cured for the time and temperature indicated inTable 14, in a N₂ atmosphere in a Despatch LAC High Performance Oven.Each of the wafers was then subjected to the indicated descum process ina March PX-500 Plasma Cleaning Tool.

The patterned films were then subjected to dilute copper etchant (25 wt% Transene APS-100, 4 sec), rinsed with water, then hard-baked (130° C.,3 min). Each wafer was then placed into a sputtering chamber (DentonExplorer 14), pre-cleaned with an argon plasma, then sputtered withtitanium (200 Å) followed by copper (2000 Å). Next, each wafer wasspin-coated with AZ 9260 and soft baked (110° C., 3 min) and imagewiseexposed to actinic radiation (900 mJ/cm2, i-line) and developed in AZ400K (1:2.5 wt/wt, 2 min), subjected to dilute copper etchant (4 sec) toremove any trace copper oxidation. After a DI water rinse the waferswere placed into an electroplating bath (Microfab SC Make-Up with SC MDbrightener and SC LO 70/30 leveler) (400 mA, 6 min). After removal fromthe electroplating bath, the wafers were rinsed with DI water an theresidual photoresist was stripped with acetone, and then the metal seedlayers removed with appropriate copper then titanium etchants, thusrevealing second metal traces on top of the various polymerredistribution layers. Electrical continuity and resistance of thesecond to first metal structures was then measured for each wafer andthe average of those measurements reported in Table 14. As it can beseen, Formulation F9 provided results equal to or better than thecommercially available CP1 and CP2 materials.

TABLE 14 Summary of RDL Device Example Data SB Cure Descum ResistanceFormulation temp/time Exposure PEB temp/time Conditions† (Ω) F9 100, 5375 — 180, 120 † 1.9 F9 100, 5 375 — 180, 120 † 1.8 F9 100, 5 375 — 180,120 † 2.2 CP1 100, 5 250 100, 5 200, 120 25/19 sccm Ar/O2, 2.1 300 W,300 mtorr, 30 sec CP1 100, 5 250 100, 5 200, 120 25/19 sccm Ar/O2, 2.0300 W, 300 mtorr, 30 sec CP1 100, 5 250 100, 5 200, 120 25/19 sccmAr/O2, 2.3 300 W, 300 mtorr, 30 sec CP2 120, 3 327 — 150, 30 † 1.7 320,30 CP2 120, 3 327 — 150, 30 † 2.2 320, 30 CP2 120, 3 327 — 150, 30 † 1.8320, 30 †Unless otherwise noted, 60/60 sccm of CF₄/O₂ was used in alldescum operations at 600 W, 300 mtorr and for 60 sec.

By now it should be realized that the polymers composition embodimentsin accordance with the present invention provide tailorablecharacteristics that allow for such compositions to provide desirablelevels or values of stress, modulus, dielectric constant, elongation tobreak and permeability to water vapor for the applications for whichthey are intended. Further, it should be realized that such embodimentshave been shown to be self-imageable, and can be formulated as eitherpositive tone or negative tone compositions to allow for the formationof a desired device, such as the chip stack, RDL and CIS devicesdescribed above and below.

We claim:
 1. A microelectronic or optoelectronic device comprising oneor more of a redistribution layer (RDL) structure, a chip stackstructure, a CMOS image sensor dam structure, where said structuresfurther comprise a thermo-oxidatively stabilized polymer havingrepeating units derived from a norbornene-type monomer in accordancewith Formula A:

where s is selected from 0 to 3, t is selected from 2 to 4, u is aninteger from 1 to 3 and R⁵ is selected from methyl, ethyl, n-propyl ori-propyl, and an additive package comprising a phenolic antioxidant anda synergist.
 2. The microelectronic or optoelectronic device of claim 1,where the synergist of the antioxidant package is one or more orbis(4-(tert-butyl)phenyl)amine (Steerer Star),bis(4-(2-phenylpropan-2-yl)phenyl)amine (Naugard 445),bis(4-(tert-pentyl)phenyl)amine or bis(4-methoxyphenyl)amine(Thermoflex) and the phenolic antioxidant is one or more of2,2′-((2-hydroxy-5-methyl-1,3-phenylene)bis(methylene))bis(4-methylphenol)(AO-80), 6,6′-methylenebis(2-(tert-butyl)-4-methylphenol) (4-PC) or3,5-bis(1,1-dimethylethyl)-4-hydroxy benzenepropanoic acid (Irganox1076).
 3. The microelectronic or optoelectronic device of claim 2, wherethe diaryl amine of the antioxidant package comprisesbis(4-(2-phenylpropan-2-yl)phenyl)amine NG-445) and the hindered phenolcomprises2,2′-((2-hydroxy-5-methyl-1,3-phenylene)bis(methylene))bis(4-methylphenol)(AO-80).
 4. The microelectronic or optoelectronic device of any of claim1, 2 or 3 where the norbornene-type monomer in accordance with Formula Ais trioxanonanenorbornene (NBTON) or tetraoxadodecanenorbornene(NBTODD), 5-(3-methoxypropanoxy)ethyl-2-norbornene (NB-3-MBM) or5-(3-methoxypropanoxy)methyl-2-norbornene (NB-3-MPM).
 5. Themicroelectronic or optoelectronic device of claim 4 where thethermo-oxidatively stabilized polymer further comprises repeating unitsderived from one or more norbornene-type monomers selected fromnorbornenyl-2-trifluoromethyl-3,3,3-trifluoropropan-2-ol (HFANB),norbornene methyl glycidyl ether (MGENB),5-decylbicyclo[2.2.1]hept-2-ene (DecNB),5-phenethylbicyclo[2.2.1]hept-2-ene (PENB),5-phenbutylbicyclo[2.2.1]hept-2-ene (PBNB), ethyl3-(bicyclo[2.2.1]hept-2-en-2-yl)propanoate (EPENB),246-(bicyclo[2.2.1]hept-5-en-2-yl)hexyl)oxirane (EONB),bicyclo[2.2.1]hept-5-ene-2-carboxylic acid (Acid NB) andnorbornenylpropanoic acid (NBEtCOOH).
 6. The microelectronic oroptoelectronic device of claim 2, where said device comprises a CMOSimage sensor dam structure.
 7. The CMOS image sensor dam structure ofclaim 6, where the repeating units of the thermo-oxidatively stabilizedpolymer are derived from two or more monomers selected from NBTON,NBTODD, NB-3-MPM, NB-3-MBM, PENB, PBNB, EONB, DecNB and MGENB.
 8. Themicroelectronic or optoelectronic device of claim 2, where said devicecomprises a chip stack structure.
 9. The chip stack structure of claim8, where the repeating units of the thermo-oxidatively stabilizedpolymer are derived from two or more monomers selected from NBTON,NBTODD, NB-3-MPM, NB-3-MBM, HFANB, EPEsNB and NBCOOTMS.
 10. Themicroelectronic or optoelectronic device of claim 2, where said devicecomprises a redistribution layer (RDL) structure.
 11. The redistributionlayer (RDL) structure of claim 10, where the repeating units of thethermo-oxidatively stabilized polymer are derived from two or moremonomers selected from NBTON, NBTODD, NB-3-MPM, NB-3-MBM, HFANB, DecNB,EONB, EPEsNB, NBCOOTMS and MGENB.
 12. A thermo-oxidatively stabilizedpolymer composition comprising repeating units derived from two or moremonomers selected from NBTON, NBTODD, NB-3-MPM, NB-3-MBM, HFANB, EPEsNB,NBCOOTMS, EONB, PENB, DecNB and MGENB, a synergist selected from one ormore of bis(4-(tert-butyl)phenyl)amine (Steerer Star),bis(4-(2-phenylpropan-2-yl)phenyl)amine (Naugard 445), andbis(4-methoxyphenyl)amine (Thermoflex), a phenolic antioxidant selectedfrom one or more of2,2′-((2-hydroxy-5-methyl-1,3-phenylene)bis(methylene))bis(4-methylphenol)(AO-80), 6,6′-methylenebis(2-(tert-butyl)-4-methylphenol) (4-PC) or3,5-bis(1,1-dimethylethyl)-4-hydroxy benzenepropanoic acid (Irganox1076), and a casting solvent selected from MAK, GBL or PGMEA.
 13. Thethermo-oxidatively stabilized polymer composition of claim 12, furthercomprising one or more additives selected from 3-GTS (KBM-403E), CGI-90,Denacol EX321L, SIB-1832, BY16-115, Phenothiazine, CHDVE, Si-75,TrisP-3M6C-2(5)-201, TrisP-3M6C-2(4)-201, GSID-26-1, CPTX, and RhodorsilPI
 2074. 14. A thermo-oxidatively stabilized, positive tone polymercomposition comprising a casting solvent selected from MAK, GBL andPGMEA, said casting solvent having dissolved therein monomers derivedfrom NBTON, HFANB and EPEsNB, and the additives A0-80, NG445, DenacolEX-321 L, BY16-115, Si-75, SIB-1832, and TrisP-3M6C-2(5)-201 orTrisP-3M6C-2(4)-201.
 15. A thermo-oxidatively stabilized, negative tonepolymer composition comprising the casting solvent MAK or PGMEA havingdissolved therein, monomers derived from NBTON, MGENB and optionallyDecNB and the additives Rhodorsil PI 2074, CPTX, Phenothiazine, CHDVE,AO-80, NG-445, 3-GTS (KBM-403E), Si-75 and SIB-1832.